Starbuck has displayed many signs of someone who is at risk of suicide including erratic behaviour and mood swings, increased use of alcohol, depression, sense of worthlessness (the "screwup"), agression, giving things away (the statue of Athena given to Adama shortly before her death), isolation from loved ones, and previous attempts (the dual with "Scar" was clearly more than just an enemy threat elimination or a competition with Kat to be the top gun).